Coal tar-derived conductive pigment/polyvinylidene fluoride composite for Joule heating

Abstract

The fast-increasing demand for high-performance carbon conductive paints has motivated the use of inexpensive precursors and easy-to-manufacture methods to scale up production. The performance of carbon conductive paints highly depends on the precursor types, carbonization conditions and the coordination between carbon pigment and binder. This work investigated the effect of precursors (by-products of coking industry including coal tar pitch, anthracene oil, naphthalene oil, and washing oil) on the structure and properties of carbon pigment, as well as the influences of binders polyvinylidene fluoride (PVDF), styrene-butadiene emulsion, and acrylic emulsion on the electrothermal properties and adhesion of carbon paint coating. The conductive pigment prepared from coal pitch has nano-sheet structure, high sp2 content, large sp2 cluster size and high disordered structure, resulting high carrier concentration and mobility, and low volume resistivity. The carbon conductive coating fabricated from coal pitch-based pigment and PVDF (PC-PVDF) has good electrothermal properties, excellent stability, low volume resistivity, good adhesion and corrosion resistance. The electrical conductivity of carbon-PVDF composites prepared from coal tar pitch, anthracene oil, naphthalene oil, and washing oil as precursors were 15.7, 3.0, 4.4, and 4.0 S/m, respectively. Coal pitch-derived conductive pigment-PVDF carbon coating exhibits excellent Joule heating performance, i.e., up to 147 °C at 20 V when heating at 122 °C/min, uniform temperature distribution, and excellent reusability. This work demonstrates the potential application of coal pitch-based pigment-PVDF coating for Joule heating.